The 18-year-old has been causing a stir outside of English football’s top four divisions with his performances for Tower Hamlets and has already spent time training with Reading.
The Royals are thought to remain keen on sealing a deal, but Palace have stepped in since his time in Berkshire last month.
Reports claim that Williams has spent the last week with the south London club, impressing coaches with is ability and attitude.
The 18-year-old plays as a wide midfielder.
Non-league football has become a major talking point in recent weeks given the performances of Jamie Vardy for Leicester City.
The 28-year-old has broken the Premier League record for scoring in consecutive games 11 in 11) and is a full England international.
Just under four years ago Vardy was playing for Fleetwood Town.